title: Clinical utility of the resistive index in atherosclerotic renovascular disease.
abstract: OBJECTIVE
  This retrospective study examines the relationship between the renal resistive index (RI) and blood pressure and renal function response after open and percutaneous intervention for atherosclerotic renovascular disease (AS-RVD).
  
  
  METHODS
  From March 1997 to December 2005, 86 patients (46 women, 40 men; mean age, 68 +/- 10 years) underwent renal duplex sonography (RDS), including main renal artery and hilar vessel Doppler interrogation, before treatment of AS-RVD. Of these, 56 patients had open operative repair, and 30 had percutaneous intervention. The RI (1-[EDV/PSV]) was calculated from the kidney with the highest peak systolic velocity (PSV). Hypertension response was graded from preprocedural and postprocedural blood pressure measurements and medication requirements. Renal function response was graded by a >or=20% change in estimated glomerular filtration rate (eGFR) calculated from the serum creatinine concentration.
  
  
  RESULTS
  Comorbid conditions, baseline blood pressure, and preoperative renal function were not significantly different between open and percutaneous groups. Baseline characteristics that differed between the percutaneous vs open group were higher mean age (71 +/- 11 years vs 67 +/- 9 years; P = .05), kidney length (11.3 +/- 1.3 cm vs 10.7 +/- 1.2 cm; P = .02), proportion of patients with RI >or=0.8 (50% vs 21%; P = .01), and proportion of bilateral AS-RVD (37% vs 80%; P < .01). After controlling for preintervention blood pressure and extent of repair, postoperative eGFR differed significantly for RI <0.8 or >or=0.8 when all patients (P = .003) and percutaneous intervention (P = .008) were considered. Specifically, eGFR declined from preprocedure to postprocedure in the patients with RI >or=0.8 after percutaneous repair and in the group analyzed as a whole. Neither systolic nor diastolic pressure after intervention demonstrated an association with RI. Considering all patients and both groups, multivariable proportional hazards regression models demonstrated that RI was predictive of all-cause mortality. RI was the most powerful predictor of death during follow-up (hazard ratio, 6.7; 95% confidence interval, 2.6-17.2; P < .001).
  
  
  CONCLUSIONS
  After intervention for AS-RVD, RI was associated with renal function, but not blood pressure response. A strong, independent relationship between RI and mortality was observed for all patients and both treatment groups.
authors.affiliation: Division of Surgical Sciences, Section on Vascular and Endovascular Surgery, Wake Forest University School of Medicine, Winston-Salem, NC.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Crutchley
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Pearce
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Craven
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Stafford
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Edwards
authors.forename: Kimberley J
authors.initials: KJ
authors.lastname: Hansen
mesh_terms: D000368:Aged; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D001783:Blood Flow Velocity; D001794:Blood Pressure; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006978:Hypertension, Renovascular / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000098:blood supply* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D012079:Renal Circulation; D051437:Renal Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D014655:Vascular Resistance; D014656:Vascular Surgical Procedures / Q000009:adverse effects
chemical_list: D003404:Creatinine